It is known to form (spin) a fiber using a hydrogenated norbornene-based ring-opening polymer having a melting point, or an amorphous cycloolefin having a glass transition temperature.
For example, Patent Literature 1 discloses a fiber-like formed article that is formed (spun) using a polymer having a melting point. Patent Literature 1 discloses forming a fiber at a spinning speed equal to or higher than 200 m/min (see the examples of Patent Literature 1).
Patent Literature 2 discloses a fiber and the like that are formed of a cycloolefin polymer that has a glass transition temperature of 70° C. or more and a cycloolefin content of at least 40 mol %, and exhibit excellent heat resistance, chemical stability, strength, nonwoven fabric production capability, shape followability, and shape retention capability, and methods for producing the same. Patent Literature 2 recommends winding the melt-extruded resin substantially without stretching the resin (i.e., effecting melt spinning so that the extrusion speed is equal to the winding speed).
It is known to pelletize a powder (resin powder) of a cycloolefin polymer (e.g., copolymer of ethylene and cycloolefin) using a method that melts the cycloolefin polymer using an extruder, and pelletizes the molten cycloolefin polymer using a pelletizer (see Patent Literature 3). According to this method, the resin powder (that is heated inside the cylinder) is melted due to heat applied by the cylinder, and subjected to shearing when caught in the screw. As a result, cyclohexane-insoluble microparticles are included in the resulting resin pellets, and a problem occurs when the resin pellets are used to produce an optical material.
Patent Literature 4 proposes preheating the resin in order to prevent a situation in which the resin is subjected to excessive shearing.